Changing the clocks twice a year for Daylight Saving Time is linked with the onset of cluster headaches, severe headaches on one side that recur over days and weeks.

To many people, turning back the clocks means a glorious extra hour of sleep. But for others, the end of Daylight Saving Time means a bout of excruciating pain.

The time change can spell disaster for unlucky sufferers of cluster headaches, the sudden, severe headaches described by the National Institutes of Health as "one of the most painful conditions known to man." Cluster headaches come on suddenly and manifest as debilitating pain on one side of the head, and typically occur around the same time each day for a period of seven days or more.

Scientists are still probing exactly why they happen, but the change to the body's circadian rhythms triggered by the time switch is thought to play a role in that and other health issues that can pop up at this time of year, according to Dr. Shelby Harris, Director of the Behavioral Sleep Medicine Program at Montefiore Medical Center in the Bronx.

"Any time you (change) the body's clock even by an hour, it really throws off all the hormones in your body," Harris said. "Our biological clocks are so well set that even an hour's difference in light exposure" can create changes in the body, she said.

Even if you don't get headaches, Daylight Saving still has the potential to mess with your head, so to speak. Difficulty falling and staying asleep due to changing clocks can lead to drowsiness and irritability, which in turn can lead to health hazards ranging from overeating to the exacerbation of conditions like sleep apnea.

While "springing forward" an hour seems to wreak the most havoc — both heart attacks and car accidents are known to spike the day after Daylight Saving begins — "falling back" comes with its own set of potential health hazards.

Even though you might enjoy an extra hour of sleep on Saturday night, 'falling back' can mess with your sleeping and waking schedule in the days that follow.

(wavebreakmedia/Getty Images/iStockphoto)

"The first thing that I see is that people struggle with staying awake in the evening and keeping to their original routine," Harris said. "They want to sleep a little later in the morning, so they need to be able to stay up more."

The fall time change also ushers in months of short days and long nights for people in higher latitudes, which can bring on symptoms of seasonal affective disorder and depression, according to Dr. Marlynn Wei, a psychologist in private practice in the East Village.

"A lot of people with the seasonal change and having less exposure to daylight can have more symptoms of depression," she said. "People might be more irritable. They're feeling less energy and just feeling more down, like the winter blues."

Try these tips to prep your body and mind for the new season:

Get ready for the time change a few days in advance. If 10 p.m. is your regular bedtime, 9 p.m. is going to feel like normal following the time change, and that's when you'll start to feel sleepy, says Harris. Staying up 20 minutes past your normal bedtime on the Friday and Saturday before falling back can help you stick to your schedule later in the week.

If you can, switch the clocks back during the daytime on the Saturday before Daylight Saving ends, suggests Dr. Shelby Harris of Montefiore Medical Center. Eating your meals and doing other daily activities at the 'new' time can help your body asjust.

(karam miri/Getty Images/iStockphoto)

If you don't have a strict schedule on Saturday, change your clocks during the late morning or early afternoon, Harris adds. Shifting your other activities, like meals, earlier will help you adjust more smoothly.

Even though you're getting an "extra" hour of sleep in fall, try to stick to your usual Saturday night routine. "What people tend to do in fall is stay up even later on Saturday night," Harris says. "They kind of overdo it, and they end up losing sleep."

Limit your alcohol, caffeine and nicotine the day before the time change. The substances can impact your ability to fall asleep, Harris says, and they can also trigger headaches.

In the coming weeks, get as much daylight as you can. Take a walk during the day or spend your lunch break outdoors to boost your mood and energy levels, Wei suggests: "Even 20 to 30 minutes outside will make a big difference."

Don't forget to exercise. Working out in the evening, but not too close to bedtime, can help keep you from going home and crashing after work, Wei says.

Try light therapy for energy. Light boxes are relatively inexpensive at about $20 to $30, and these small lamps can be helpful for most people, Wei says, though people with bipolar disorder should consult a doctor first. "It's best in the morning, so if you're putting on makeup or having your coffee, have it at a 45 degree angle at your side for about an hour," Wei says.